1. Field of the Invention
The invention relates to a magnetic mounting of a rotor shaft relative to a stator and, more particularly, to a magnetic mounting using a high-Tc superconductor.
2. Description of the Related Art
Magnetic mountings of this type serve for the largely loss-free mounting of a rotor shaft relative to a stator. One possible application is, for example, the mounting of a motor shaft. When such a magnetic bearing is in operation, the superconductor is cooled to a temperature of approximately 77 K, for example using liquid nitrogen or by a refrigerating machine. The permanent-magnetic elements provided on the rotor shaft and the flux guide elements of the arrangement located on the rotor-shaft side are also cooled to temperatures of approximately 77 K via the small spacing relative to the superconducting structure, the bearing gap which spaces the two arrangements apart having a width of only 1.5 mm. If, then, ambient air has unimpeded access to the bearing gap, the air moisture contained in the ambient air will freeze out of the air in the bearing gap on the cold bearing parts and the bearing gap will therefore be narrowed by ice. The bearing gap thus freezes shut in the course of time.
In order to counteract this, it is known, for example, to introduce dry gaseous nitrogen into the bearing gap. The throughflow or scavenging of the bearing gap with dry nitrogen which is induced thereby prevents moist air from penetrating into the bearing gap. This has the disadvantage, however, of a relatively high outlay in terms of apparatus and the consumption of scavenging gas.